QUESTION 5 (20 Marks)

Use the information provided below to answer the following questions.

As a demand planner at Grootegeluk Mine, you want to determine the monthly sales forecast of coal (in tonnes). Table 1, below, depicts the volume of coal sold by the mine for each of the 12 months of 2022.

Table 1: Volume of coal sold monthly during 2022 Year	Monthly volume (tonne	s)
Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
2022	21	23	34	37	40	51	54	50	48	36	39	42

REQUIRED:

Using the data provided in Table 1, answer each of the following questions:

5.1. Using the three-month weighted moving average method, calculate the monthly forecasts for April 2022 to January 2023 by assigning weights of 0.1, 0.3, and 0.6 (the oldest data to the most recent data, respectively) (Round off forecast values to one decimal place). (10 marks)

5.2. Calculate the mean absolute deviation (MAD) of the forecasts for April 2022 to December 2022 (Round off the answer to two decimal place). (5 marks)

5.3. Calculate the mean absolute percentage error (MAPE) of the forecasts for April 2022 to December 2022 (Round off the answer to two decimal place). (5 marks)

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